Bipolaris Leaf Spot and Brown Patch Control in a Mixed Stand of Ryegrass and Tall Fescue
with Heritage and Headway Using Lawn Applicator Technique, 2007
Materials and Methods:
This study was conducted in front of the ‘Research Tee’ at Philadelphia Country Club, located in
Gladwyne, Pennsylvania. The stand was a mix of tall fescue and perennial ryegrass and maintain similar to a
high-end lawn. No fungicides were applied to the turf the spring prior to the initiation of the study.
Site was supplied with 1.5 lb N/1000 ft2 on 19 May and again with 0.5 lb N/1000 ft2 from 19-25-5
Anderson’s Contec. Soil was a native clay-loam with a pH of 6.6 and 4.3% organic matter. Turf was mowed
three times per week with a Z-turn rotary mower at three inches. Irrigation was applied to the area as needed to
prevent drought stress and occurred in the early evening when preformed. On treatment days, materials were
applied to a dry canopy using a lawn care simulation application technique. Mowing and irrigation was
restricted for 48 hours following all applications. Plots were 7.5 ft x 5 ft and arranged in a randomized complete
block with four replications.
Fungicides were applied using an FMC spray gun calibrated to deliver 2.0 gallons 1000ft2, with
relatively large droplets. Treatment application rates and dates are footnoted in table 1. Ratings were taken
when disease and turf quality differences were observed within the study. Data were subjected to analysis of
variance (ANOVA) using ARM and significantly different means were separated according to the Least
Significant Difference (LSD) test (P ≤0.05).
Results:
Leaf spot, caused by Bipolaris species, was microscopically identified in the site on 14 June. All
fungicide treated plots (0.0- 2.0%) had less blighting from the leaf spot, when compared to the untreated control
(29%). Similar trend was observed on 29 June, in which all treated plots had significantly less blighting from
leaf spot, than the untreated control. Also on that date, plots treated with Headway at 1.0 fl oz/1000ft2 had an
average of 3.5% blighted while all other fungicide treated plots were disease-free.
All plots were re-treated on 1 July. Brown patch blighting did not occur until 19 July. All treated plots
remained disease-free until 16 August (approximately 45 days since last treatment). Brown patch blighting in
the untreated control was 18.0, 27.0 and 41.0, on 26 July, 2 August and 10 August, respectively. On 16 August,
all fungicide-treated plots had less brown patch blighting than the untreated control, however, the least amount
of disease was observed in plots treated with Headway at 1.5 fl oz/1000ft2. Plots treated with Headway at 1.0
oz/1000ft2 had significantly more blighting, when compared to plots treated with Headway at 1.5 fl oz/1000ft2.
In a previous study conducted with same application in 2006, close to 45 days of control was achieved with
Headway applied at 1.5 fl oz/1000ft2. While other treated plots had minor levels of blighting. Data from this
years’ trial and the pilot trial conducted in 2006 suggest that lawn care applicators could achieve acceptable and
cost effective levels of brown patch control on a mixed stand of tall fescue, fine fescue and perennial ryegrass
with two properly timed fungicide applications. Another benefit of these applications would be the control of
the endemic disease, leaf spot.
Overall turfgrass quality was rated three times over the course of the trial. On 29 June, while leaf spot
blighting was occurring in the untreated plots, all fungicide treated plots had significantly higher and
agronomically great quality. On 19 July, and when brown patch blighting occurred, a similar trend was
observed. On the 10 August, rating date, the quality in the untreated control had dropped to 5.0 and was poor
due to color and blighting by brown patch. All fungicide-treated plots had acceptable levels of quality and
should be considered commercially acceptable for a high-end lawn care situation. No significant differences
were observed among fungicide treatments for their level of quality.
Table 1. Leaf spot and brown patch control in 3 inch mixed perennial ryegrass and tall fescue as influenced by various fungicide application
% Plot Area Blight by Bipolaris y
% Plot Area Blighted By R. Solani y
Rate
14 June
29 June
19 July
26 July
2 August
10 August
16 August
(oz/1000ft2)
Headway
1.0 fl
2.0 b z
3.5 b
0.0 b
0.0 b
0.0 b
0.0 b
5.5 b
Headway
1.5 fl
0.0 b
0.0 b
0.0 b
0.0 b
0.0 b
0.0 b
0.0 c
Heritage WG
0.2 oz
2.0 b
0.0 b
0.0 b
0.0 b
0.0 b
0.0 b
1.5 bc
Heritage TL
1.0 fl
0.0 b
0.0 b
0.0 b
0.0 b
0.0 b
0.0 b
1.5 bc
Untreated
29.0 a
33.3 a
12.5 a
18.0 a
27.0 a
41.0 a
36.0 a
P>F
0.0001
0.0001
0.0001
0.0001
0.0001
0.0001
0.0001
x
All treatments were applied on 25 May 2007. The 28-day sequential treatments were re-applied 1 July, 2007. All treatments were applied using a
lawn-care applicator gun using large droplets in 2 gallons of water per 1000 ft2 at 38 psi.
y
Percent of plot area blighted was visually assessed on a 0 to 100 scale, with 0= no blighting and 100=entire plot area blighted.
z
Means in each column followed by different letters are significantly different (P ≤0.05) according to the Fischer’s Protected least significant difference
test.
Treatment x
Table 2. Three Inch Turf Type Tall Fescue Quality as Influenced by Various Fungicides and Application Intervals, 2006.
Treatment
Headway
Headway
Heritage WG
Heritage TL
Untreated
P>F
x
2
Rate (oz/1000ft )
1.0 fl
1.5 fl
0.2 oz
1.0 fl
-
29 June
9.00 a
9.13 a
9.13 a
9.13 a
6.83 b
0.0001
Overall turfgrass quality (0-10) y
19 July
9.13 a
9.25 a
9.13 a
9.13 a
6.15 b
0.0001
10 August
9.00 a
9.00 a
9.00 a
9.08 a
5.00 b
0.0001
All treatments were applied on 25 May 2007. The 28-day sequential treatments were re-applied 1 July, 2007. All treatments were applied using a
lawn-care applicator gun using large droplets in 2 gallons of water per 1000 ft2 at 38 psi.
y
Turfgrass quality was rated on a 1- 10 scale with 7.7= the minimal acceptable level for a tall fescue lawn in the mid-Atlantic and 10= optimal
greenness, density and appearance.
z
Means in each column followed by different letters are significantly different (P ≤0.05) according to the Fischer’s Protected least significant difference
test.
Date
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1
Degree F and %
Average Ambient Air Temperature and Humidity, Gladwyne, PA 2007.
100
90
80
70
60
50
Ave temp
%Humidity
40
30
20
10
0